Strap stretching mechanism



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STRAP STRETCHING MECHANISM 7 Sheets-Sheet 2 A mm mm,

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STRAP STRETCHING MECHANISM Original Filed Dec. 21, 1939 Y SheetS-Sheet 5 f 5 2 INVENTORS.

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STRAP STRETCHING MECHANISM Original Filed Dec. 21, 1959 g @& wk Mmww s wk IN V EN TORS. lfldlam C M71955 2112 424,

BY James Rm x5 Patented Jan. 2, 1951 STEAL? STRETCHING MECHANISM William G. Childrcss, Oak Park, and James M. Royal, Chicago, 151., assignors to Acme Steel Company, Chicago, IlL, a corporation of Illinois Original application December 21, 1939, Serial No. 319,276, new Patent No. 2,375,769, dated May 15, 1945. Divided and this application September 21, 1943, Serial No. 503,264

Claims. I

This invention relates to improvements in strap stretching apparatus and its purpose is to provide improved means by which a flexible binder, such as a fiat or substantially flat flexible steel strap, including strap having a concaved cross section may be drawn taut around a box or package, or about a group of such objects, preliminary to uniting the overlapping strap ends by sealing apparatus or the like. The present application is a division of a copending original application, Serial No. 310,276, filed on December 21,1939, now Patent Number 2,375,769, granted May 15, 1945, in which there is described and claimed an improved strap sealing apparatus which is combined in one unitary portable tool with the strap stretching apparatus of the present invention. This invention is an improvement upon that described and claimed in United States Letters Patent No. 2,097,444, dated November 2, 1937.

The present invention may be embodied in a combination strap stretching and sealing tool in which opposite end portions of a strap passed around a package are held by relatively movable gripping devices carried by the base plate of the apparatus, which is adapted to seat upon the package, these gripping devices being capable of relative movement by the actuation of a lever for the purpose of drawing the strap taut around the package, after which another lever is operated to cut off the strap from the source of supply, to move a seal into engagement with the overlapping strap ends and then to deform the seal and the strap ends to provide an interlocking joint. The present improvement may also be embodied in a tool which performs the single function of drawing the strap taut around a package and placing its ends in overlapping relationship in readiness to permit the formation of a joint between these ends by a separate tool or apparatus.

The present invention has for its principal object the provision of improved apparatus of the type referred to which may be conveniently and efficiently operated and which is strong and durable so that it may be used with particular advantage in drawing taut metal straps of heavy gauges although capable of other uses. A further object is to provide strap sealing apparatus comprising improved stretching mechanism for drawing a strap taut around a box or package, this stretching mechanism comprising relatively movable gripping devices and actuating mechanism for moving these gripping dogs to draw the strap taut in combination with an additional gripping device adapted to hold the supply portion of the strap between successive operations of the actuating mechanism so that the strap may be drawn taut in successive increments without releasing the strap between successive operations of the actuating mechanism. Another object is to provide improved strap stretching mechanism adapted to draw a strap taut around a package and comprising two relatively movable gripping dogs for holding the strap during the stretching operation and also a third gripping dog for holding the supply end of the strap between successive operations of the stretching mechanism, said stretching mechanism embodying a lever which is connected to release two of said gripping devices from the strap when it is moved to a predetermined position. Another object is to provide strap sealing apparatus comprising a base plate adapted to seat upon the surface of a box or package, said base plate having parts over which the opposite end portions of the strap are adapted to extend in combination with gripping devices mounted over the base plate for cooperating therewith to hold said portions of the strap and a retaining member adapted to prevent the removal of the strap ends laterally from their positions beneath the gripping dogs, said. retaining member and at least one of said gripping dogs being automatically removed to inoperative positions by a predetermined operation of mechanism which is provided for effecting relative movement of the gripping dogs for the purpose of drawing the strap taut. Still another object is to provide strap stretching apparatus comprising improved means for mounting and actuating relatively movable gripping dogs by which the opposite end portions of a strap are held. Other objects relate to various features of construction and arrangement which will appear more fully hereinafter.

The nature of the invention will be understood from the following specification taken with the accompanying drawings in which one embodiment of the invention and a modification of a part thereof are illustrated. In the drawings,

Figure 1 shows a front elevation of one form of strap stretching and sealing apparatus embodying the present invention, the apparatus being positioned upon the upper surface of a box or package about which a flat flexible metallic binder has been passed;

Fig. 2 is a perspective view of overlapping strap ends which are united by one form of interlocking Fig. 3 is a perspective View of one form of channel-shaped metal seal adapted to be used with the apparatus illustrated in Fig. 1; Fig. 4 shows an irregular horizontal section taken on the line 4%4 of Fig. 1; e L A Fig. "5 shows a partial vertical section taken on the line 5-5 of Fig. 4;

Fig. 6 show an enlarged vertical section taken on the line 6-6 of Fig. 4, illustrating the sealing head in its extreme elevated position in it is adapted to receive a seal from the lower end of the magazine. e I I Fig. 7 shows a vertical section taken on the line 7-7 of Fig. 6;

Fig. 3 shows a vertical section taken on the line 88 of Fig. 6;

Fig. 9 shows a vertical section taken on the line 99 of Fig. 6; e

Fig. 10 shows a vertical section taken on the linel0 l0 ofFig.6 A I Fig'. ll shows 'a v'e rtioajlfsection taken on the line "i Lei"! ofFig. 1, illustrating thesealing jaws .arid the ihovobie cutting blade in their elevated fi s 'fi 7 i.

Fig. '12 is a partial seetionalview similar to thatof Fig. 11 showingt'lie relative positions of 7 parts oh-L i "th seai i head has been lowered to cause ajseal to ernbraoe the overlapping strap ends and after the j'a'wshav'e been actuated to fbend the'se'al' about, 'tlie'strapends and to deform the strap "and seal to provide an interlocking 'J'oint; p

Fig 13 is a partialiro'nt elevation, similar to "that or Fig. .1, owing is modified construction ofthei'novable gripping dogjwhich, in this form,

is mounted upon an ecce tric;

Fig. 14is1a'top plan view or the modified oohstructionshown in Fig.13;

F jl5 is "a. vertical section taken on the line gripping dog andthe operating lever when the dog i n ne em tw th F tr Fig. 16 is a front elevation, similarto Fig. l,

with parts invertical section, when the apparatus embodies the ;modiiied f orm of gripping dog ,shown in Fig. l6, illustrating therelative positions of the parts when the movable gripping dog and the holding dog are both out of engagement with the strap; V Fig. 17.is an irregular v'erticz'tlsectio'n taken on the line jll-l-l of Fig. p I

:Fig. 18 is a perspective view of the movable gripping dog shown inFig. 13;

Fig. 19 is a perspective view of the dog operatstrap from the source of "supply and applying a 5 seal to the overlapping strap ends to form 'an interlocking joir'i't. A illustrated in the drawiir'ig's, the invention oomprises an integral frame having 'a base plate 25 adapted to seat upon the surface of a box or package 2 5 about which a fiat "flexible steel strap '2'} is passed. lhe base plate 2 5 is provided "with two forwardly project- 'ingflarig sfi anaz's over which the free end 'portion"2 3?- of the strap extends, the strap bridgifig the gap 25 between "these flanges which is the region in which the interlocking joint is subsequently formed. After passing around the box or package 26, the supply end portion 21 of the strap is carried over another flange 23* which also rests upon the surface of 'th'e be); or package 26 and which projects forwardly from a block 28 secured upon a sliding bar 29 arranged to move on the base plate parallel to the strap. The free end portion 271' of the strap is adapted to be secured upon the base flange by a gripping dog 36 which is pivotally mounted on a pin 3i projecting in a forward direction from the upwardly extending web portion 25 of the base plate. flhe gripping dog is retained in position on the pin 31 by a cotter pin 32 which extends transversely through an aperture on the outer end of the pin 31 and the gripping dog is normally moved into engagement with the end portion 27* of the strap by a coil spring 32 which is 1m 1 the 69 nd t f r er e t bear n a'g ai r'istthe horizontal frame portio n 25 which 'is carried by the v rtigo-1 web hortio zt oithefb se fplate'. The gripping dog 3'llfis, provided ion its i re edge w th? serrat a r r ta nte be e h 1 6 side 9 I g i re 2 o the th s Serfiat r f mbei fi e toward the 'r ght'as viewed 1g. 1, fron -a vertical plane containing the axis of the pivot pin 3i so that a pull upon the 's'trap toward the left, as v e n t llwi tend to t te t i the dog J39 upon the "strap, while a 'pull upon the stifapfin the opposite d rection will tend to release it from its position beneath the dog. I The gripping dog is provided between the grippingfsur face 39% "and the pin 31 th an inwardly extending inclinedslotji-Ill through which the supply portion 2% or the strap "esgtehoin passing from a reel or other source of supply. The grippin dog 39 has a handle iiil fittiri'gover the inner end or the dog, as shown in Fig. Fl, andjproject'ing end-wise beyond the base plate so that it may be engaged by the ange -so: the operator for raising the grippingdo'g ou or oohtoo with thestrap end 2'1 againsttheeo np ressionoi the spring 33.

} 'l'he supply portion 2ft? of the strap is adapted to be engaged on its upper side by a-gripping dog which is mounted on the block 28 by which the flange 23 is carried. This gripping dog is pivotally mounted upon a pin tea which fits within thebore of a hollow shaft 3'! by which the sliding bar 29,;previously referred to, is actuated. As shown in Fig. 4, the' pin 36 has a head 36 which fits against the outer face or the grip- ;pin'g dog 35, while the other'end thereof is engaged by-a transverse pin '38 which extends between two diametrically opposed 'lugs 37* projecting endwise from the extremity of the hollow shaft 3?. The spaces between the lugs 37 'are such that 'a considerable angular movement or the shaft "3"! about the pin 3B is permitted without causing the transverse pin 38 to be "engaged by the lugs ar "as shown in'Fig. 5. The gripping dog '35 is "inclined downwardly and toward the left, as viewed in Fig. 1, and the lower end thereof is provided with a "s'errated surface te adapted to engage the upper surface or the strap 27*. not to this inclination of the ri ping dog, o movement of the gripp n dog and of 'th'eblock 22 mo direction tending to tighten the strap '2'? about the to or package, houses the r f e @198. iii in i i iii th strap, whine a moviiint or the "block as "in the reverse direction tends to release the strap from the gripping dog. A curved flange 28 is formed integrally with the block 28 and overlies the gripping dog 35, thus providing a curved bearing surface for the curved upper extremity 35 of the dog. As shown particularly in Fig. 4, the gripping dog is provided between its front and rear edges with a transverse slot 35 adapted to receive a coil spring 39 which is mounted around the pin 36 with one of its extremities engaging the wall of the slot 35 and with the other extremity engaging a shoulder 23 formed on the flange 28 of the block 28 so that the spring tends normally to move the gripping dog into engagement with the strap. The gripping dog is notched out on its front side to provide a flat transverse shoulder 35 which is positioned opposite to the flat face 36 which is formed on one side of the head 36 of the pin on which the gripping dog is mounted as shown in Fig. 1. The head 36 of the pin is set into this notch and the shoulder 35 is spaced slightly from the flat face 3!? so that a limited relative angular movement of the gripping dog with respect to the pin 36 is permitted.

Referring now to the means for effecting relative movement of the gripping dogs 30 and 35, the block 28 which carries the gripping dog 35 is provided with a horizontally extending flange or plate 28 which seats upon the sliding bar 29, as shown particularly in Figs. 4 and 5. The plate or flange Ml has a, longitudinally extending rib or key l8 formed on its under side to fit within a longitudinal keyway 29' which is formed in the sliding bar, and the plate or flange la is secured to the bar by screws 29 which extend upwardly from the bar through apertures in the plate as shown by dotted lines in Fig. 5. In this way, the block 28 has a rigid connection with the sliding bar 29 which, in turn, is mounted to slide longitudinally of the base plate in an undercut guideway 25 which is provided partially by flanges formed integrally with the base plate and partially by a block 4!] which is secured to the base plate and has a flange overlying the upper edge of the sliding bar as shown by dotted lines in Fig. 6. The block 23 is notched out to receive the block 40 and is adapted to move over this block 40 when the sliding bar 29 is reciprocated. The block 28 is further provided with a forwardly projecting arm 1'8 located to the right of the flange 28 as viewed in Fig. 1, and at a higher level so that it overlies the strap and prevents it from swinging upwardly away from the flange 28 The reciprocation of the sliding bar 29 is effected through the medium of a pinion 31* which is formed integrally with the hollow shaft 31, as shown in Figs. 4 and 9. This pinion meshes with rack teeth 4g which are formed on the block 40, previously referred to, so that when the shaft 3! is rotated the block 28 and the bar 29 are moved longitudinally of the apparatus, that is, parallel to the strap 21. The shaft 3'! is journaled at one end in a bushing ll which is mounted in an aperture formed in the block 28 and the other end thereof is mounted in a bushing 42 which is mounted in a bearing block 13 secured to the plate 28 of the block 28 by means of socket screws 44. A screw M engages the block 43 to prevent the removal of the pin 38, as shown in Fig. 9, and the flange of the base plate which overlies the rear edge of the bar 29 is notched out to permit the block 43 to be inserted axially over the end of the shaft 31 and the bushing 4|.

The lugs 3'! on the shaft, which were previously referred to, project beyond the bearing block 43, as shown in Fig. 4. The shaft 3? is rotated in these hearings by the stretching lever 4 5 which is provided at its outer end with a spherical handle portion 45 and which is provided at its inner end with a hub portion 45 having a central bore of rectangular cross section which is fitted by the correspondingly shaped portion 37 of the shaft, thus providing a driving connection between the lever and the shaft so that when the shaft is oscillated in a plane extending parallel to the strap 2?, the shaft 3? is moved angularly about the pin 36 and the bar 29 is caused to move longitudinally on the base plate. As shown in Fig. 9, the portions of the pin 36 which are engaged by the spring 39 and which lie within the portions 31* and 31 of the shaft are reduced in diameter, thus limiting the frictional resistance to the turning of the shaft about the pin on which the gripping dog is mounted. When the lever 45 is moved toward the left from the position shown in Fig. 1, the bar 29 moves in the same direction, ius causing a movement of the gripping dog 35 toward the gripping dog 36, with a resulting stretching of the strap 2'? around the box or package 25. Inasmuch as the gripping dog 35 tends to release itself from the strap upon movement of the block 28 toward the right, as shown in Fig. 1, it will be apparent that the lever "25 may be reciprocated any number of times with corresponding reciprocations of the gripping dog 35 and the alternate gripping and releasing of the strap by this dog so that the strap 2? may be drawn taut around the package in successive increments until the desired degree of tautness is reached. An additional gripping dog ll is provided, as hereinafter described, for holding the strap 21 between successive operations of the lever 45. The transverse pin 38 in the end of the pin 36 on which the gripping dog 35 is mounted is so positioned with respect to the lugs 37* extending endwise from the shaft 31 that, as the lever 45 approaches the extreme right-hand position shown in Fig. 1, these lugs engage the pin 53 and rotate the pin 36 with the shaft 51, with the result that the head 35 of the pin engaging the shoulder 35 on the gripping dog, causes the gripping dog to be lifted out of engagement with the strap portion 2. against the tension of the coil spring 39, thus automatically releasing the strap from the gripping dog upon an extreme movement of the lever 45 so that the strap may be passed from its position beneath the gripping dog after it has been drawn taut.

In addition to the gripping dogs 35! and 35, the apparatus of the present invention comprises a third gripping dog 41 which is pivotally mounted upon the outer end of a pin is, as shown particularly in Figs. 1 and 6. The pin 48 is secured in the upwardly extending frame portion 25 which is formed integrally with the base plate 25 and the lower end of this gripping dog is provided with a serrated surface l? which is adapted to coact with that portion of the upper side of the strap portion Z'l which rests upon. a flange ZE formed integrally with the flange portion 25 and extending in a forward direction over the flange 25 and above the strap end 21 as shown in Fig. 6. The gripping dog ll is inclined down- Wardly and toward the left, as viewed in Figs. 1

these figures, causes this dog to increase its grip ilponthe strap whileiuponimovement of the strap in the other direction, the gripping dog 1 will terid 'toirelease its grip upon the strap 'so that the strap may slidefreely beneath it. lbe-grip Jp'i'ngdog t! is normally moved into engagement with the strap portion 'Zi above the flange 25 by a coil spring 49 which is mounted'around the ipin M; Within a notch 4T formed :in the upper side of the gripping dog, as illustrated .in :Fig. one end of this spring engages the flange 25 of the base plate and the other end :engages the bottom of the notch 21 as shown in Fig. '6, so that the spring is normally moved toward the flange 25K This'g'ripping dog 41 is=capable of being moved out of engagement with the strap,

simultaneously with the release of the gripping dog 35, upon movement o'f the stretching lever "45 to the extreme right-han'd position, shown in Fig. 1,'this'relea'se of the gripping dog be'ing eifectedby'a pin or lever 58, shown particularly in Fign8. Thislever is provided at its forward end with a spherical extremity 56 'whichis adapted to rock within a socket ll formed in the rear side of the gripping dog near its-lower edge and,

atan intermediate point, the pin or lever Eilis T.

provided with -'a rounded bearing portion 59' which is'adapted to rock'wi-thin an aperture 25 formed in the upwardly extending frame portion 25 "f the-baseplate. The rear portion 52 or the pin or lever :50 projects over the sliding bar '29, as shown in-Fig. 8, and when the sliding bar 29 reaches-a predetermined position, this portion 'of the lever 50 is adapted to be engaged by an actuating pinl5i which is resiliently mounted in -a recess in a bearing block :52 secured to the upper side of thesliding bar 29 by means of socket screws 53. 'A coil-spring 5 3 surrounds the stem of the pin 5! 'within the block and this stem, extending through an opening at the end of the recess, is engaged bylock nuts Eli The bearing; pin 5e 7 is retained in its position engaging -the socket in'the gripping dog ill and the bearing 25 in the frame structure by-a flange 25 which extends upwardly from the fl'angewhich over- -hangs 'the rear edgeof the bar'29. gripping dog 55- is moved out of engagement with the-strap by swinging the-stretching lever 45 to its extreme right-hand position, as viewed in Fig. 1, the gripping dog 41 is simultaneously "moved out of engagement with the portion 2? of the strap by the engagement of the pin =5I with theipinor lever 59. The gripping dog i! =may thusbe'elevated to permit'the removal of thesuppIy end ofthe strap after the partpreviously passed around'thebox or package has been i cut off by the operation of the cutting mechanism hereinafter described, in order that the supply end maybe placed'beneath the'grippin'g 'dog 33 in'readiness forstra'pping anotherb'ox'or package. The spring 5 causes thezplunger "5| =to-project normally-a considerable"distance from the right endofthe block 52 and is of suificient strength toc'ause'the pin -56 to operate the'gripping dog 4? except when the teeth of the dog are bitinginto a strap which is undertensi'on \vhenthe dogs! is engaging a strap underten- 'sion. and also when the dog'has been elevated by the first engagement of the pin 5i with-the .pin 59, the spring as permitsa continued movement ef the bar :2 9 :for effecting a further elevation of the dog35. During the operation-of drawing-a straptaut, the gripping dog serves as a takeup "device 'for holding the strap between successive s 'trtchin g operations of the reciprocating gripping dog 35. Upon eachMmovement-of the When the 8 dog 35 toward the :left, as "viewed in :Eig. 1, the 's ap, being relatively stiff, is adapted to slide beneath th'e gripping dog #31. During the 'opera- -tion of fldrawing a strap taut, the lever '45 :is not moved to the extreme position shown ainiFig. 1 where it causesboth of the gripping dogs .35 and *4 to release the strap.

'l'l-"he apparatus is provided .with means .for holdinglthe strap "ends in th'eir proper overlapping relation'shipwhile the strap is being idrawn'taut around the package. :Ilhis retaining me'ans :is shown particularly in Figs. 1, 4, 56 :and and ficompris'es :a hook member whichzis 'pivotally mounted on a pin 56 secured in the walls of a slot :25 formed in a vertical flange or web 12:? "of the base plate which extends zupwardlyfrom and in spaced relation to the .fiiange :25, fprieviouslyireferred tosthere'being at rectangular notch 25 between these flanges, as shown in Fig. .10, which receives :the inner wedges o'f the t'overlapping portions tl and ?2l of the strap. Ihe ilowe'r edge ':'of the =fiange 25 is inclined downwardly "and inwardly to facilitate the insertion :of the strap 'ends to theiriproper positions. .vVhen thus inserted, the downwardly "extending projection ES -at the end ofthe retainingimember is adapted to prevent withdrawal of "the strap .ends, the member :55 being normally forced downwardly zto the-Strapretaining position'shown in Fig. '10, by means of a Icoil spring 57 which I-is :mounted in a recess "25 formed in'the flange 25 and which bears against the upper :side of the :member :25. The member is provided rearwardly =of the lpivot,=,pin 53 with a pin 55 which projects into the path of a cam :58 secured by .a rivet :59 :on the sliding 'bar -2 9. 'As shown :in 'Figs. :5 and 10, l-thecam '53 is vprovided with an inclined surface which is adapted'tmengage and depress the arm .55 of the retaining'member, thus elevating the body portion of the retaining member-against the compression of thespring Eiuntil-it isin such a position that the overlying strap ends may 'be freely removed from their positions above the flange 25*. The camriiS *is preferably so locate'd on the'slidingbar '29 that the selevationof the retaining member 55 1s efiected simultaneously with the elevation oi the gripping dogs-te and Al.

ihe mechanism for-cutting off the strap from thesource-of supply-and=for applying atseal to the overlapping strap ends is -claimed in said original :copending application and will \be only -.briefly referred to here :for the purposeof :explaining the -.surroundings in which the \strap stretching :mechan-ism operates. ll'heseal -.employed with the apparatus is .preferably the channel-shaped metal 1 body .63, shown .in Fig. 3, which comprises a back wall til and side walls 59 which diverge fromthe back wall and which .are preferably provided midway between their ends with .punched projections se adapted to provide pointeto-point contacts between theside walls-oi adjacent-seals when'a pluralityof seals are arranged in a nested relationship in r a stack. .Thelback wallsiofvthe seal arepreierablyprovided tvith apertures fi l -sothat a stack-of seals may .be temporarily secured together by -a piece of wire or thelike insertedthrough theregistering apertures. After.the stack of seals isplaced in -the magazineof the sealing apparatus-the wire .is withdrawmand the seals are then adapted to be fed in succession from thebottom of-the stack to the-jaws of .the sealing mechanism by 'which they are applied -to the overlapping ends oil-the strap which has been drawn taut 'by the strap stretching mechanism of the .present invention.

This form of seal and the resulting package are described and claimed in Letters Patent Nos. 2,062,098 and 2,062,099, granted on November 24, 1936.

When a seal of the type illustrated in Fig. 3 is applied to overlapping strap ends by apparatus of the present invention, the back wall Gil overlies the supply portion 21 of the strap and the jaws of the sealing apparatus are adapted to bend the side walls 65 downwardly and inwardly so that they underlie and contact with the lower end portion Z'I of the strap. The supply portion 21 of the strap is cut off from the source of supply in such a manner that the transverse cut end 21 is located in close proximity to and preferably in substantial alignment with one end of the back wall 69* of the seal. The final act of the sealing operation effected by the sealing device is that of shearing the lateral edges of the strap ends and the seal along the parallel lines Bil as shown in Fig. 2, thus forming cuts wh ch extend through the margins of the seal and through the marginal portions of the strap ends. The cuts are arranged in pairs and the jaws are adapted to deflect the metal between the cuts of each pair downwardly to form angularly disposed lugs 60 thus providing a series of abutting shoulders between the seal and the strap ends wh ch prevent relative longitudinal movement of the strap ends. The seals 63 are preferably formed of steel or other metal which is comparatively stiff and rigid but sufficiently ductile to permit them to be bent about the strap ends and to retain their form after be ng bent.

The seals are supplied to the sealing head of the apparatus from a seal storage magazine 55 which is mounted on the base plate 25, as shown in Figs. 1 and 8, and this magazine extends upwardly at the side of a housing 67 which contains mechanism by whch the seals are fed from the magazine to the sealing head hereinafter referred to. A handle is secured to the frame or base plate 25 to permit the entire apparatus to be moved about. The seals are fed downwardly in the magazine by a spring actuated member II which is adapted to move downwardly in the magazine as the seals are withdrawn from the lower end thereof.

The movable head 80 which receives the seals from the magazine 65 and applies them to the overlapping strap ends comprises a hollow frame or housing 8i, shown in Fig. 11, which is mounted to slide vertically toward and from those portons of the overlap ing strap ends which extend across the gap 25 between the flanges 25 and 25 of the base plate. A flange 34 is mounted to move vertically in the frame SI and is arranged to actuate the sealing jaws 85 which are shown particularly in Figs. 11 and 12. These jaws arepivotally mounted on p ns 86 and they are adapted to be moved about their pivots by a pair of links 31 which are pivotally connected to the jaws by the pins 89 and pivotally connected to each other and to the plunger 84 by the pin 88 upon vertical reciprocation. of the plunger 84. It w ll be apparent that the jaws 85 may he opened to receive a seal Bil between their lower hooked extremities or closed upon each other for the purpose of applying the seal to the strap ends.

Each jaw member 85 is made up of bending and cutting dies which are arranged alternately and which are so formed that when the jaws close upon each other the bending dies first bend the sde walls of the seal about the overlapping strap ends, after which the cutting dies shear the edges of the seal and the strap ends to form the interlocking joint above referred to. In order to hold the seal in the jaws when it is first positioned therein and during the applicaton of the seal to the strap ends, a supporting saddle or pressure member 93 is mounted between the jaws and arranged to engage the back wall of the seal so that the edges of the side walls of the seal are retained in contact with the extremities 85 of the jaws, as shown in Fig. 11.

The downward movement of the plunger 84 is opposed by two co'l springs IOU which are secured at their lower ends to a transverse pin IOI extending through the lower part of the central web of the plunger, as shown in Fig. 11, and which have their upper ends attached to a cross bar I02 carried by the frame 8|. After the plunger 84 has been moved downwardly within the frame 8| to effect a closing of the jaws 85 upon the seal, the extended springs will return the plunger to its upper position with a resulting separation of the lower portions of the jaws and this action of the springs is supplemented by the positive operating mechanism by which the plunger 84 is operated. This operating mechanism includes a lever I29 which is shown in its retracted position in Fig. 1 corresponding to the elevated position of the head 89 in which position the jaws 85 are adapted to receive between them a seal fed thereto from the magazine 65. When the lever I20 is swung upwardly and toward the left from the position shown in Fig. 1, the first effect of this operation is to cause the head BI! to be lowered bodily to position the seal 60 carried by the jaws upon the overlapp ng strap ends and, upon further movement of the lever I20 in the same direction, it actuates certain mechanism which moves the plunger 86 downwardly within the frame 8| so that the jaws are closed upon each other and caused to assume the final position illustrated in Fig. 12. Upon reverse movement of the lever I20, the jaws 85 are first opened to release the seal and the enclosed strap ends and the head is then elevated to the normal position shown in Figs. 1 and 11 in readiness to receive anotherseal from the magazine. When the sealing head is in this upper position, it is adapted to receive a seal which is automatically fed to the jaws by a plunger I35, shown in Fig. 6, which is mounted for sliding movement in the frame 6'! and which is controlled in its operation by the movements of the sealing head.

In addition to controlling the actuation of the seal feeding mechanism, the movable head 80 also serves to control the actuation of the mechanism by which the supply portion of the strap is cut off after the strap has been drawn taut and when this cutting operation takes place the two ends of the strap are placed in proximity to each other in readiness to receive the seal. This cutting mechanism, which is illustrated in Figs. 4, 6, 11 and 13. comprises a shearing blade I 54, which is stationary during the cutting operation, and a relatively movable blade I55, both of which are carried by a lever I56 which is pivoted on a stud I 51 mounted in the upright portion 25 of the frame, as shown particularly in Fig. 11. The two blades are attached to the lever I56 by a bolt I60 and the blade I55 is adapted to have pivotal movement about this bolt during the operation of shearing the supp y po tion of the strap which is positioned Ov r the blade I54. This blade I54 is positioned slightly above the base flange 25 of the frame to permit the end portion 2'! of the strap to bepassedbe- "neath'the head .in'order that the strap may be cut off in proximity to the position to be occupied .by the end of the seal subsequently applied to the overlapping strap ends and, to permit'the lower-- ing of the head during the sealing operation, the .lever 156 is swung about the bolt I 51 through the engagement of a pin I65 with a cam slot formed betweentheside plates and the head 8 I, as illus- "tratedin Figs. 1 and 11. As the head approaches its lowercondition, the pin I65 engages an inclined portion of the cam slot which causes the shearing blades to be moved out of the path of 'the head and, during the final movement of the head the pin I65 travels in the vertical portion of the cam slot. Upon reverse movement of the ,head, a reverse movement of the shearing blades takes place and the movable shearing blade IE5 is elevated through the operationof a link I 66 whichconnects the head with the forward end of this blade. During the downward movement of the head 80 the slot Nit in the link I66 allows the side plated I of thehead to move downwardly to a sufficient extent to engage the projection 4 55 on the upper shearing blade, thereby causing a shearing :movement of'that blade to cut off the strap. .In this way, the shearing mechanism is automatically operated to cut ofi the supply portion of the strap in such'a position that the cut edge Of the strap will lie in close proximity to the seal when the seal is applied to the strap ends.

.Inthe operation of this improved apparatus, thestrap stretching tool, having its magazine 65 filled with .a stack of seals 60, is placed in osition With.'ltS base plate resting'on the upper surface .or against a vertical side surface of the box or package to be strapped. The free end 21 of a :strap isthenpassedbeneath the gripping dog 36 which is elevated by pressing on the lever This end of the strap is located, as shown in Fig.

1, so that it extends beneath the shearing blade 154 and over the flange 25 of the base plate, :the retaining member 55 being then elevated to permit the convenient insertion of the strap through the previous movement of the lever r to the extreme right-hand position shown in Fig. 1. The strap 2'! is then passed around the package lzfi and the supplyportion 27 thereof is inserted beneath the-gripping dog 35'and beneath theretaining member andthe' gripping. dog ll,

The :rnovement :of the lever v45 toward the left .115 then continued to draw the strap taut around the package. If one movement of the lever is not suilicient, itmay be returned toward its initial position "and'reciprocated several times in order "to bring about the desired degree of tautness'in the strap. Upon each return movement of the :lever '45 toward the right, .as viewedin Fig. 1, the

ripping dog :35 will automatically elevatesum- :12 cientlyto-slide. over the surface of the strap,'due to the inclination of the gripping dog. But the gripping dog t? will retain its hold upon the supply portion of the strap so that there will be no loss of tension while the lever 45 and .the gripping dog 35 are making a return stroke. The strap will ordinarily have sufiicient stifinessso that, oneach stretching operation of the lever 45, a portion of thestrap will be pushed along beneath the gripping dog 4! due to the inclination of this gripping dog. Having drawn the strap taut around the package, the lever I 2.0 is then operated to cut off the supply portion of the strap and to apply a seal to the overlapping strap ends in the manner set forth above and as more fully described in said copending original application.

In Figs. 13 to 20, inclusive, there is shown a modification of the means for mounting and actuating the movable grippingdog 35, heretofore described, which is intended to permita more ready release-of the strap from the tool in case it be desired to do this without completing the formation of the interlocking joint, as, for example, when it is foundafter drawing the strap taut that it is not in the desired position on thepackage. Under such circumstances, the tension in the strap tends tohold the'gripping dogs 35 and ll down in their gripping positions and it isdiflicult to elevate them to release the strap. Means have-therefore been-provided forfacilitating this release. In the drawings of this modificatiomthe same reference numerals are used as were used heretofore to designate the partswhich are the same in construction and the present description will be confined tothe part which-are different. In the modified form, the gripping dog 175,

which corresponds in position and general function to-the-gripping'dog -35 heretofore described,

is provided with a serrated gripping surfac H5 adapted to engage the supply portion ZI -of the strap above the flange 28 of 'the movabl block 28 and this gripping dog ismounted upon the eccentric portion Ii-G of a pin I16 which is in all respects similar to the pin 36 heretofore described except for this eccentric portion and some other details of the forward end thereof. The dog I15 is provided with an upwardly extending arm I15 andacoil spring IT! is mounted around the eccentric portion I1 fi of the pin with one end Ill thereof engaging one side of the arm "5 and'with the other end iTl thereof hooked over a part 228 of the block 28 so that the spring tends normally to move the gripping dog into engagement with the strap. The part 228 is a portion of a rectangular hollow bracket which extends forwardly from the block 28 and within which the gripping dog H5 is located. The forward end of the pin 116 is provided with an axially concentric cylindrical portion I76 which is journaled "in a bushing mounted in the front transverse member 228 of this bracket and, between the parts Ilii and I16 the pin is provided with a portion I76 of hexagonal cross section which fits within a corresponding aperture in the hub portion of a lever I18 arranged to extend upwardly adjacent the arm 575' of the gripping dog. The lever I18 has a latch member H9 pivoted upontheiupper end thereof and this latch member has a flange 119 extending substantially parallel to the flangellfi 'whi'ch projects laterally from the upper end of the lever. A coil spring I88 is mounted between the flanges I73 and I79 so that the hook portion I19 of the latchmember is normallyheld in interlocking engagement with the upper extremity of the arm [15 formed on the adjacent gripping dog. The arm H has an inclined face 115 adjacent its upper end so that when the lever H8 is moved toward the left from the position shown in Fig. 16, the latch member will automatically interlock with the arm of the detent in the manner shown in Fig. 13.

Assuming that the strap 21 is drawn taut around. the package and that the supply end 21' of the strap is being held by the gripping dog 41, as shown in Fig. 13, it is first necessary to release the strap from this gripping dog and this is efiected by first transferring the tension of the strap to the other gripping dog I15 and then finally releasing the latter dog from the strap. To do this the lever 45 is moved from the position shown in Fig. 13 to the position shown by full lines in Fig. 15, thus permitting the dog I15, which is then latched to the lever 118, to move into engagement With the strap under the influence of the spring I'll. Then, upon further movement of the lever 45 in the same direction to the position shown by dotted lines in Fig. 15, the tension in the strap is taken by the dog I15 and the pin 50 which controls the dog 4! is still engaged by the pin 5| so that the endwise thrust on the portion of the strap between the dogs I15 and the dog 41, coupled with the action of the spring 49 associated with the dog 47, operates to raise the dog 41 out of engagement with the strap. The operator then presses on the flange I19 of the latch member to release the lever I18 from the arm [15 of the dog H5, whereupon continued downward pressure on the flange I19 operates the lever I18 to rotate the pin I15 and thereby cause the eccentric portion I16 to raise the dog I15 out of engagement with th strap. To limit and adjust the movement of the dog I15 toward the flange 28 of the block, a stud l8l is adjustably mounted in the part 228 of the block to engage the lower end face of the dog, as shown in Fig. 15, and this stud may be held in adjusted position by a lock nut I82.

Although one form of the invention and a modification thereof have been shown and described by way of illustration, it will be understood that it may be constructed in various other embodiments coming within the scope of the appended claims.

We claim:

1. The combination in strap stretching apparatus, of a base plate, a bar movable on said base plate, means including a hollow shaft for effecting movement of said bar, a pin mounted within said hollow shaft, a gripping dog mounted on said pin, and means actuated by a predetermined rotation of said shaft for actuating said pin to efiect angular movement ofsaid gripping dog.

2. The combination in strap stretching apparatus, of a base plate, a bar movable on said base plate, a block carried by said bar and having a flange adapted to support a strap, a hollow shaft journaled in said block, a pin mounted in said shaft, a gripping dog mounted on said pin and adapted to engage said strap on said flange, means for rotating said shaft, and means actuated after a predetermined rotation of said shaft in one direction for effecting angular movement of said pin to release said gripping dog from said strap.

3. The combination in strap stretching apparatus, of a base plate, a bar slidable on said base plate, a block carried by said bar and having a flange on which a strap is adapted to rest, a hollow shaft journaled in said block, a pin mounted in said shaft, a gripping dog mounted on said pin, a spring tending normally to move said gripping dog into engagement with said strap, means for rotating said shaft, and means actuated upon a predetermined rotation of said shaft in one direction to turn said pin and thereby move said gripping dog out of en agement with said strap.

4. The combination in strap stretching apparatus, of a base plate having a flange adapted to support a strap, a gripping dog pivotally mounted on said base plate and adapted to engage the upper side of said strap, said gripping dog having a socket, a pin engaging said socket, and means for actuating said pin to release said gripping dog from said strap.

5. The combination in strap stretching apparatus, of a base plate having a flange adapted to support a strap, a gripping dog mounted on said base plate and adapted to engage the strap on the side thereof opposite said flange, 2. spring tending normally to move said gripping dog into engagement with said strap, a pivotally mounted pin engaging said gripping dog, and means for rocking said pin about its pivot for moving said gripping dog out of engagement with said strap.

6. The combination in strap stretching apparatus, of a base plate having a flange adapted to support a strap, a gripping dog mounted on said base plate and adapted to engage the strap on the side thereof opposite said flange, a spring tending normally to move said gripping dog into engagement with said strap, a pivotally mounted pin engaging said gripping dog, a bar slidable on said base plate, and means actuated by said bar for moving said pin to cause said gripping dog to release said strap.

'7. The combination in strap stretching apparatus, of a base plate having a flange adapted to support a strap. a gripping dog mounted on said base plate and adapted to engage the strap on the side thereof opposite said flange, a spring tending normally to move said gripping dog into engagement with said strap, a pivotally mount d pin engaging said gripping dog, a bar slidable on said base plate, and a resiliently mounted member carried by said bar for engaging said pin upon movement of said bar and thereby causing said gripping dog to release said. strap.

8. The combination in strap stretching apparatus, of a base plate, a pair of relatively movable gripping devices carried by said base plate for holding a strap with its ends overlapping, means including a sliding bar for eifecting relative movement of said gripping devices to draw the strap taut, a retaining member extending transversely of said strap ends and adapted to maintain said ends in overlapping relation, means tending normally to move said retaining member to its operative position, and means including a cam carried by said bar operated by a predetermined movement of said bar after the strap has been drawn taut for actuating said retaining member to release said strap ends therefrom.

9. The combination in strap stretching apparatus, of a base plate, a bar slidable on said base plate, a block carried by said bar and having a flange on which a strap is adapted to rest. a hollow shaft journaled in said block, a pin mounted in said shaft, a gripping dog mounted on said pin, a spring tending normally to move said gripping dog into engagement with Said strap, means for rotating said shaft, means actuated upon a predetermined rotation, of said shaft in one direction to turn said pin and thereby move said gripping dog out of engagement with said strap, said pin having an eccentric portion upon which said gripping dog is mounted; means normally causing said pin and said gripping dog to move together, and means for releasing said last-named means to permit said gripping dog to be turned aboutsaid eccentric portion. i

10. The combination in strap stretching apparatus, of a base plate, a bar slidable on said base plate, a block carried by said bar and having a flangeon which a strap is adapted to rest, a hollow shaft journaled in said block, a pin mounted in said shaft, a gripping dog mounted on said pin, a spring tending normally to move said gripping dog into engagement with said strap, sans for rotating said shaft, means actuated'upon a predetermined rotation of said shaft in one'direction to turn said pin and thereby move said gripping dog out of engagement with said strap, said pin having an eccentric portion upon which said gripping dog is mounted; a lever fixed in said pin adjacentsaid gripping dog, a latch member normally 'securing said lever to said gripping dog, and means for releasing said latch member and permitting said lever to turn said pinand thereby cause said eccentric portion to elevate said gripping dog.

WILLIAM C. CHILDRESS. JAMES M. ROYAL.

REFERENCES CITED 7 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,784,025 Norton Dee-9, 1930 1,891,767 Ketcham Dec. 20, 1932 1,939,746 Whitman Dec. 19, 1933 1,988,534 Abbott Jan. 22, 1935 1,988,730 Harvey Jan. 22, 1935 1,989,669 Harvey Feb. 5, 1935 2,087,655 Prestwich July 20, 1937 2,229,786 Abbott Jan. 28, 1941 2,324,609 Watt July 20, 1943 

